[1]} explored the effect of the temperature of the helium burning shell (T\(_{\rm {He}}\) ) on \(^{16}\) O/\(^{18}\) O. In particular, \(^{16}\) O/\(^{18}\) O drops below unity for shell temperatures in the range T\(_{\rm {He}}\)  \(\approx 2.5-3.5 \times 10^{8}\)  K. Thus, dLHdC stars could be associated with WD merger remnants that have T\(_{\rm {He}}\)  in this range. For shell temperatures outside this range, \(^{16}\) O/\(^{18}\) O increases to RCB-like values, suggesting that RCB stars either have T\(_{\rm {He}} < 2.5\times 10^{8}\)  K or T\(_{\rm {He}} > 3.5\times 10^{8}\)  K.
